1. Field of the Invention
This invention relates, generally, to conveyance systems. More particularly, it relates to a versatile conveyance system that can accommodate packages of varying widths.
2. Description of the Prior Art
In conventional conveyor belt systems, a pair of fixed position guide rails flank the conveyor belt. These systems work well in those applications where the breadth of the packages, containers, or other objects being conveyed from one point to another are of a common breadth. However, they cannot be used in a conveyor system that handles objects of varying widths.
Where objects of varying widths are to be conveyed, the transverse or lateral spacing of the guide rails must be adjustable. Inventors have developed several conveyor systems having adjustable guide rails. For example, U.S. Pat. No. 5,211,280 to Houde discloses an assembly where the position of one of the guide rails may be adjusted by a rack and pinion assembly. The position of the other guide rail, however, cannot be changed by said rack and pinion assembly. An internal cam mechanism is employed to adjust the lateral spacing between guide rails in the structure disclosed in U.S. Pat. No. 5,291,988 to Leonard. A tapered clamp performs that function in the assembly disclosed in U.S. Pat. No. 5,626,221 to Ledingham. U.S. Pat. No. 5,692,596, also to Ledingham, discloses a split support rod held by a clamp. Another clamp assembly is disclosed in U.S. Pat. No. 5,701,991 to Helmetsie. U.S. Pat. 6,050,396 to Moore discloses a rack and pinion assembly that interconnects both guide rails to a single pinion. There are at least another half dozen patents disclosing other mechanisms for varying the transverse or lateral spacing between longitudinally extending guide rails.
All of the earlier assemblies perform their respective intended functions. However, they are mechanically complex and as a result they require frequent maintenance and adjustment. Such work sometimes requires that the conveyor line be shut down at great expense. What is needed, then, is a much simpler assembly that requires minimal maintenance and adjustment.
Some of the earlier assemblies also have width-adjustment means the operation of which is time-consuming. For example, one embodiment of the ""396 patent to Moore requires an operator to manually turn a knob to effect rotation of a drive shaft that carries a pinion gear that is meshingly engaged to rack gears upon which are mounted rail supports that carry the guide rails of the system. It is a time-consuming job to rotate the knob until the desired spacing between guide rails has been achieved. Moreover, rack and pinion gears are not easy to fabricate and they may disengage from one another. In another embodiment of the Moore assembly, a reversible motor performs the shaft rotation function. However, such motors are not inexpensive. In both the rack and pinion embodiment and the reversible motor embodiment, there is no easy way to lock the guide rails into position once the desired spacing has been achieved.
What is needed, then, is a better means for adjusting the spacing between conveyor system guide rails. The improved means should neither require nor exclude use of a motor. However, it should enable a machine operator to manually perform the width adjustment in a very precise, fast and easy way. Moreover, a self-locking means is needed as well.
However, in view of the prior art in at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.
The longstanding but heretofore unfulfilled need for a conveyor apparatus of elegant yet effective design is now met by a new, useful, and nonobvious invention that has utility in conveyor and conveyance systems.
The novel apparatus for varying the lateral spacing between guide rails in a conveyor assembly or conveyance system includes a straight drive shaft of elongate construction that is mounted for rotation about a longitudinal axis of rotation. A rotation means is provided for selectively rotating the drive shaft in a first direction about its axis of rotation and in a second direction about said axis, the second direction being opposite to the first direction. The rotation means includes a linkage means formed by a rigid center link and two rigid outboard links. All of the links are of flat, straight configuration. The center link is centrally apertured to accommodate the drive shaft. Moreover, the center link is mounted for conjoint rotation with the drive shaft so that rotation of the drive shaft effects simultaneous and corresponding rotation of the center link. In a preferred embodiment, the drive shaft is noncircular in transverse section and the central aperture formed in the center link is complementally formed therewith. The center link is pivotally connected at its opposite, outboard ends to inboard ends of the respective outboard links. Each outboard link has an outermost free end and a slideably mounted mounting block is pivotally connected to the respective outermost free ends of the outboard links. An upstanding rail support member is mounted to each of the slideably mounted mounting blocks. A first guide rail is mounted to a first rail support member and a second guide rail mounted to a second rail support member.
Accordingly, rotation of the drive shaft in a first direction effects convergence of the first and second guide rails and rotation of the drive shaft in a second direction opposite to said first direction effects divergence of the first and second guide rails.
Several means are disclosed for enabling rotation of the drive shaft. In one embodiment, a control gear is mounted on the drive shaft for conjoint rotation therewith in longitudinally spaced apart relation to the center link so as not to interfere therewith and a pinion gear is disposed in meshing engagement with the control gear. The pinion gear is mounted for conjoint rotation at the distal end of an elongate control shaft having a control knob mounted on a proximal end thereof for conjoint rotation therewith. In this way, manual rotation of the control knob in a first direction effects rotation of the control gear and hence said drive shaft in said first direction. Manual rotation of the control knob in a second direction opposite to the first direction effects rotation of the control gear and hence the drive shaft in a second direction.
A second means for enabling rotation of the drive shaft includes a reversible motor means having an output shaft secured to the drive shaft for conjoint rotation therewith.
A third means for enabling rotation of the drive shaft includes a bell crank means having a first end mounted to the drive shaft for conjoint rotation therewith and a second end, disposed at a fixed angle to the first end, to which is pivotally secured an elongate control arm.
There are three illustrative means for effecting rotation of the bell crank, although equivalent means are within the scope of this invention.
A first means is manual, i.e., a second or free end of the elongate control arm is adapted for manual engagement so that manual displacement of the elongate control arm in a first direction effects rotation of the drive shaft in a first direction and manual displacement of the elongate control arm in a second direction effects rotation of the drive shaft in the second direction.
In a second means, an elongate screw actuator pivotally engages and displaces the free end of the control arm.
A third means includes a pneumatic cylinder that pivotally engages the second end of the control arm. Both the screw actuator and the pneumatic cylinder provide enhanced utility because such mechanisms enable locking of the guide rails into a preselected position when the desired spacing has been set.
Guide rail sections having a bend or curvature formed therein may also be employed to enable the conveyor or conveyance assembly to follow a curved path of travel. Extension guide rails of straight configuration are slideably mounted to the curved guide rail sections and are connected thereto by a stop block and rod assembly. The opposite ends of each curved guide rail section are axially bored to slideably receive an associated rod and the free end of each rod is secured to a stop block that surmounts the extension guide rails.
Thus it is understood that the primary object of the invention is to provide a novel conveyance apparatus that provides adjustable width guide rails but which has a small number of moving parts and which is free of gear arrangements.
A closely related object is to provide such a reliable and durable apparatus that minimizes maintenance problems and thus conveyor belt downtime.
Still another important object is to provide a control means that enables a machine operator to vary the lateral spacing between guide rails in a fast, precise, and easy way, free of control knobs and motors.
Yet another important object is to provide a mechanism that is self-locking so that the spacing between guard rails remains the same during operation of the apparatus.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.